This research proposes the development of a simple, selective and highly sensitive new research tool useful for investigations of RNA structure and function, and with which absolute composition analysis including identification and preparative isolation of previously uncharacterized modified ribonucleosides of any RNAs can be made at the nanogram level. Different RNAs will be quantitatively analyzed for their composition of major and modified nucleosides. The application of this chromatographic research tool will be most useful to investigations in biochemistry and molecular biology involving tRNA, mRNA, tumor and non-tumor viral RNAs. Very little is known about the influence of nucleoside modification on the function and regulatory activities of RNAs in viral transformation, protein synthesis, cell differentiation, neoplasia and suppression. Our aims include development of a new research tool for nucleoside characterization that is simple, selective, and sensitive, with: a. optimization of enzymatic hydrolysis conditions of RNAs, b. utilization of boronate gel column chromatography for selective isolation and purification of RNA hydrolysates, c. modification and advancement of high-performance liquid chromatography (HPLC) to expand the range of modified nucleosides to be separated, identified, and quantitated, d. structural confirmation of known modified nucleosides and elucidation of structure of newly isolated modified nucleosides by mass spectrometry (MS), and if needed GC-MS, Ir, UV, NMR, etc., e. development of preparative isolation (mg amounts) of modified nucleosides in RNAs for structural characterization by NPLC-MS, GC-MS, IR,UV, and NMR. f. investigations on the structure and function of initiator and other tRNAs from Friend's leukemia cells undergoing differentiation.